Dr. Gizmo.

It's Sticky Wheel That Gets The Oil

January 24, 1993|By Phil Arendt.

When I was checking the brakes on my 1990 Oldsmobile 98, I was able to remove the aluminum wheels on the front of the car with no trouble, but when it came to removing the rear wheels, they wouldn't come off. I pushed and pulled to no avail. Then I sprayed penetrating oil between the mating surfaces and let it soak overnight. The next day, I pulled on the wheels and they came off. Is there anything that I can apply to the wheels to make them easier to remove? E.J.M., Norridge

You might try applying an anti-seize compound between the drums and wheels. Another thing to do is rotate the tires more often. That should be done every 7,500 miles. If you do that, the wheels won't get stuck.

I am a widow, and when it comes to automotive matters I rely on the advice of others. I have saved many of your columns for future reference. A neighbor suggested that I should add Slick 50 to my engine oil. Should I? B.L.T., Gary

I have never used additives or treatments in any of my vehicles. Though I haven't kept all of them for more than 100,000 miles, I did drive several well beyond that. The secret to their longevity was changing the engine oil and filter every 3,000 miles or three months, whichever came first. Because I haven't used or tested the product, I can't tell you how good it is. I can tell you that all the advertising I've read about the stuff says it's the best thing since sliced bread. Also, I haven't received letters from readers stating that the product has harmed their car engine.

In a recent column, a reader had a problem with the "check engine" light coming on. I, too, had the same trouble with my 1981 Chevrolet Citation. The light in my car would turn on and off and sometimes would stay on for as long as the engine was on. I read some of my owner's manual and found references to the light turning on because of a faulty oxygen sensor. I didn't want to replace it or take the car to a mechanic for diagnosis and repair, so I checked the engine myself. I found that the air filter was dirty, so I replaced it. Guess what? The light didn't turn on after I changed the air filter. Could other readers cure their "check engine" light troubles by replacing the air filter? M.P., Colorado Springs

The air filter is even more important than you may think. The computerized fuel-management system in the car measures how much air comes into the engine. Also, the computer measures how much oxygen is in the exhaust system, via the oxygen sensor. When an air filter gets dirty and limits the amount of air going into the engine, the computer reduces the amount of fuel going to the cylinders. As the air filter clogs and chokes the flow of air, the computer fixes the amount of fuel at a certain level so the engine will run on a lean fuel mixture. At the same time, it may turn on the "check engine" light. In the Chicago area, as in many urban areas, it's important to check the air filter every 7,500 miles. The filter may need replacement at that interval.

In May of 1989, I purchased a new Cadillac from an Oak Lawn dealership. Almost from the beginning, the engine would idle at 30 m.p.h. with my foot off the gas pedal, for a distance of about five blocks. At other times the car idles at 16 m.p.h. Also, the engine speed (at idle) reads as high as 1075 r.p.m. I've taken the car to the dealership several times for this phenomenon. Each time I take the car to the shop, I'm told, "It's very common. Rolling friction causes that. We can't find anything wrong, and it doesn't do that when we test-drive it." Is what I'm told true? W.J.C., Oak Lawn

Dealership personnel forgot to tell you that it's normal for the engine to do what it does. The engine idle speed is controlled by the computer in the car. The computer adjusts the idle according to engine temperature, electrical load, accessory load, exhaust emissions, throttle angle, fuel requirements, air flow and a number of other factors. No adjustment can be made to stabilize the idle. Control the car by applying the brakes.

I have a 1983 Cadillac with a 4.1-liter aluminum engine and 114,000 miles. It has the original distributor cap and rotor, and seven of the eight spark-plug wires are original, too. Recently the engine developed a ping during slight acceleration. I had the belts replaced, changed brands of gasoline and had the engine analyzed on a computer. No problems were found, but the ping persists. What's causing the ping, and will taking a long trip to Florida cure the trouble? G.V., Westmont

I wouldn't attempt a drive to Florida until you have the wires, cap and rotor replaced, or you may be stranded. The noise you hear may be sparks from the ignition system jumping from the wires or cap to a ground such as the engine block. Or the ping could be caused by excessive carbon deposits in the engine. In that case, a trip may help remove some of those deposits and stop the ping. Also, a carbon clad exhaust gas recirculation, or EGR, valve or a faulty knock sensor may be the root of the problem. In that case, replace the valve or sensor.